I think any court would readily disagree that the words to Katie Lee's version are "anonymous"--nor do I believe Katie Lee would claim they were--, except that we may not know who is responsible for the bowdlerizations (or "adaptations", if you prefer.) Of course, since Clark's poem is now in the public domain, that has ceased to be a legal issue, though Clark should still be credited, regardless of later changes. Gertrude Ross must've obtained explicit permission for the usage and alterations of Clark's poem. Her version is no less legitimate than Katie Lee's, rather the opposite.